| Message ID | 20171108165250.GA137694@adacore.com |
|---|---|
| State | New |
| Headers | show |
| Series | [Ada] Accessibility violation flagged on anonymous access component | expand |
Index: exp_ch4.adb =================================================================== --- exp_ch4.adb (revision 254542) +++ exp_ch4.adb (working copy) @@ -11279,6 +11279,7 @@ elsif In_Instance_Body and then Ekind (Operand_Type) = E_Anonymous_Access_Type and then Nkind (Operand) = N_Selected_Component + and then Ekind (Entity (Selector_Name (Operand))) = E_Discriminant and then Object_Access_Level (Operand) > Type_Access_Level (Target_Type) then
The compiler was incorrectly generating an unconditional raise of Program_Error (and associated warnings) for returning a component with an anonymous access type within a function of a generic instance. The code that was performing this check was intended to apply only to anonymous access discriminants (as indicated by comments) but neglected to test whether the selected component was a discriminant. This was ancient code that was implemented prior to Ada 2005's additions of anonymous access types for components and stand-alone objects. The fix refines the test so that it only applies to access discriminants. The following test must compile quietly: $ gcc -c anonymous_instance.ads ---- generic package Anonymous_Generic is type Holder is tagged limited private; function Get_Ref_Named (This : in Holder) return not null access Integer; function Get_Ref_Anon (This : in Holder) return not null access Integer; private type Integer_Access is access all Integer; type Holder is tagged limited record M_Named : Integer_Access := new Integer'(1); M_Anon : access Integer := new Integer'(2); end record; end Anonymous_Generic; package body Anonymous_Generic is function Get_Ref_Named (This : in Holder) return not null access Integer is begin return This.M_Named; end Get_Ref_Named; function Get_Ref_Anon (This : in Holder) return not null access Integer is begin return This.M_Anon; end Get_Ref_Anon; end Anonymous_Generic; with Anonymous_Generic; package Anonymous_Instance is new Anonymous_Generic; Tested on x86_64-pc-linux-gnu, committed on trunk 2017-11-08 Gary Dismukes <dismukes@adacore.com> * exp_ch4.adb (Expand_N_Type_Conversion): Add test that the selector name is a discriminant in check for unconditional accessibility violation within instances.